I think the reason for the sudden jump in performance of full_width +MC is because up to now for depth <= 3, it was same as _uniform_ allocation. But for depth = 5 and more it becomes proportioning by sub-tree nodes count up to leaf nodes. It was a sub-tree count proportioning all along but we didn't notice it because sub-trees are uniform for depth<=3. So with that in mind it can be beaten f.i if I do full-width expansion to depth=5. Depth=6 would require too much memory though , which is a disadvantage for any breadth first searcher. Having said that it can perform bad for a selective tree where the shape of the upper portion of the tree is not related with the sub-tree size. Another idea applicable for the perft(13) competition would be to take the exact perft(12) results for 2-plies from the root and use that to determine the proportions for the monte-carlo simulations. The depth-first search does a static allocation, so a static allocation based on the real sub-tree size may perform better.

I agree with this. In retrospect, it would have been better to measure the effect of increased full-width search in the HGM and Peter1 methods before spending too much time on the UCT/weighted sampling methods._________________Peter Osterlund - peterosterlund2@gmail.comhttp://web.comhem.se/petero2home